Schering's potential anti-clotting blockbuster

Schering Plough's experimental blood drug could someday take on Plavix and prasugrel in the multi-billion dollar market.

ORLANDO (CNNMoney.com) -- Recently announced safety problems with Eli Lilly & Co.'s prasugrel could mean good news for Schering-Plough and its experimental anti-clotting drug TRA, but it wouldbe yearsbefore it could enter the market.

Dr. Lisa Jennings, the lead researcher for a Schering-funded study, said that its experimental drug prevents platelets from clumping without causing excessive or uncontrollable bleeding.

"The study demonstrated that the drug had a very exciting and unique effect on platelet function that no other drug has at this point," said Jennings, professor and director at the Vascular Biology Center for Excellence at the University of Tennessee in Memphis.

Schering released the test results on Wednesday at the annual conference of the American Heart Association, a forum for Big Pharma to highlight experimental drugs. $20 billion worth of name-brand drugs are expected to go off-patent in 2008, according to IMS Health.

Jennings said that Schering's TRA did not cause significant problems with bleeding, because it targeted the problematic platelets, not the beneficial ones. "It attacks the platelets that have the black hats, but it keeps the platelets that wear the white hats," she said.

This type of anti-clotting can be an effective way to prevent heart attacks and angina and possibly other symptoms of heart disease, said Jennings.

Any anti-clotting drug has blockbuster potential. For example, the anti-clotting drug Plavix from Bristol-Myers Squibb (Charts, Fortune 500) totaled $3.4 billion in sales during the first nine months of 2007. Now, Schering is introducing TRA, which is in a whole new class of anti-clotting drugs called thrombin receptor antagonists, and is betting that the drug could be a multi billion dollar blockbuster too.

But Schering (Charts, Fortune 500) has a lot of work to do before TRA has a chance to enter the lucrative market. The drugmaker presented phase 2 results on Wednesday, which are relatively early-stage. But the compound recently began phase 3 testing, the final stage in human studies before submission to the Food and Drug Administration. The drug is still at least four years away from possible approval, analysts say.

"There's good promise for this drug, assuming the profile holds up," said Robert Hazlett, analyst for BMO Capital Markets. "It has multi-billion dollar potential, but it clearly needs to demonstrate that profile in a major [phase 3] trial."

Schering spokesman Lee Davies said that TRA's lack of bleeding problems is an important distinction, giventhatEli Lilly & Co.'s (Charts, Fortune 500) prasugrel has been found to have some safety issues with bleeding.

An Eli Lilly study with its Japanese partner Daiichi Sankyo Co. Ltd comparing prasugrel with Plavix found a potentially dangerous side effect of bleeding showed up in 2.4 percent of prasugrel patients, compared to 1.8 percent in Plavix patients, but the company maintains that the drug is an effective treatment.

But Eli Lilly says prasugrel did a better job of preventing death from cardiovascular causes, heart attacks and strokes than Plavix. In the study 9.9 percent of prasugrel patients died, compared to a 12.1 percent death rate among Plavix patients according to lead researcher Dr. Elliott Antman, professor of medicine at Harvard Medical School.

Bristol disputed the findings and maintained that Plavix is safe, having been studied in 100,000 patients and prescribed to 70 million.

Lilly said it plans to file prasugrel to the FDA by the end of the year. But Michael Krensavage, analyst for Raymond James, said in an interview on Sunday that the FDA would probably not approve prasugrel without additional late-stage studies. Such studies are time-consuming and expensive, and there's no guarantee for success.

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Highlights of product-related research announced at American Heart Association conference: